Bicolor Mn-doped CuInS2/ZnS core/shell nanocrystals for white light-emitting diode with high color rendering index

Abstract

We synthesized bicolor Mn-doped CuInS2 (CIS)/ZnS core/shell nanocrystals (NCs), in which Mn2+ ions and the CIS core were separated with a ZnS layer, and both Mn2+ ions and CIS cores could emit simultaneously. Transmission electron microscopy and powder X-ray diffraction measurements indicated the epitaxial growth of ZnS shell on the CuInS2 core, and electron paramagnetic resonance spectrum indicated that Mn2+ ions were on the lattice points of ZnS shell. By integrating these bicolor NCs with commercial InGaN-based blue-emitting diodes, tricolor white light-emitting diodes with color rendering index of 83 were obtained.

Spectral broadening of Cu–In–Zn–S quantum dot color converters for high color rendering white lighting device

“…1(a)), I-III-VI type QDs generally exhibit an ill-defined absorption feature, primarily attributable to the combined effects of QD size/ shape inhomogeneity plus compositional variation [3,28,29]. Their defect-associated radiative recombination leads to an appreciably broad PL typically with an emission bandwidth of 4100 nm.…”

“…In particular, since the above QDs can possess a high photoluminescence (PL) efficiency, facile visible-emission tunabilitiy, and high absorption capability in the near UV-blue region, they have been strongly regarded as potential color converters in lightemitting diodes (LEDs) [19][20][21][22][23][24][25][26][27][28]. The charges photo-excited in those QDs recombine radiatively via intra-gap states stemming from the intrinsic presence of defects, typically affording Stokesshifted, broad photoluminescence (PL), even though their accurate transition pathway is still open to dispute.…”

Recent Progress in Quantum Dot Based White Light-Emitting Devices

“…9c, d). Dual color Mn-doped CIS/ZnS QDs with green and orange emission were integrated on blue LED chips, to realize WLEDs with CRI of 83 and LE of 61 lm/W [77]. In a recent study, an optimized non-injection method was developed to produce such Mn-doped QDs on a large scale [78], which were used to produce WLEDs with high CRI of 90 and CIE coordinates of (0.332, 0.321).…”

“…Zhang et al [75] developed a dual-emitting system of Cu-doped CdS/ZnSe core/shell QDs, with red color originating from Cu-doped CdS and green color from recombination at the Type-II CdS/ZnSe interface. These QDs were used as color converters to fabricate WLEDs on a blue LED chip, which emitted white light with CRI of 90, CIE coordinates of (0.325, 0.330) and CCT of 5850 K. Other kinds of Cd-free doped QDs with dual emission have been used as color convertors in WLEDs as well [76][77][78]. As shown in Fig.…”

Colloidal nanocrystals for quality lighting and displays: milestones and recent developments

“…As a remedy to this problem, doping the QDs with metal ions can be helpful because the long-wavelength emission associated with the dopants cannot be absorbed by the QDs themselves. Within this approach, Huang et al synthesized Mn-doped CuInS 2 /ZnS QDs [41]. In these QDs, Mn ions were doped in the shell of the QDs so that two-color emission can be observed from the same QD.…”